Fig. 3

iHBFC^CD105 support luminal epithelial growth and TDLU-like branching morphogenesis. Comparison of the capacity of iHBFC^CD105 and iHBFC^CD26 to induce human breast epithelial morphogenesis. a Phase contrast micrographs of luminal breast epithelial cells co-cultured for 16 days on passage 40 iHBFC^CD105 (left) or iHBFC^CD26 (right) (bar = 100 μm). Only iHBFC^CD105 facilitate elaborate TDLU-like branching morphogenesis. b Double immunofluorescence staining of luminal epithelial/iHBFC co-cultures with K19 (red) and MUC1 (green; bar = 100 μm). Note the staining of correctly polarized MUC1 in K19⁺ structures in both co-cultures. c Illustration of difference in induced branching morphogenesis by iHBFC^CD105 and iHBFC^CD26, respectively, by low magnification imaging and segmentation in ImageJ of branching morphogenesis in luminal epithelial/iHBFC co-cultures stained by peroxidase for K19 (brown). Segmented images show epithelial structures projected in black pixels (bar = 1000 μm). d Dot plot depicting the inductive capacity of seven pairs of iHBFC^CD105 (left) and iHBFC^CD26 (right) measured as the number of luminal epithelial structures per square unit area using luminal epithelial cells from five different biopsies. Consistently, iHBFC^CD105 have higher inductive capacity (asterisk indicates significance at p < 0.05 by Wilcoxon signed-rank test)